Electric motor



Oct. 12 1926. 1,602,744

' s. c. BENSON ELECTRIC MOTOR Original led Oct. 25., 1921 :7 .W v mm 2m5 m 0 J 0U. 05

Patented Oct. 12, 1926.

UNITED STATES PATENT OFFICE.

SAMUEL G. BENSON, OF HABRISVILLE, OHIO, ASSIGNOR OF ONE-FOURTH TO J.' J.ROBY, OF CLEVELAND, OHIO, ONE-FOURTH '[10 R. W. MOORE, AND ONE-FOURTH TOL. S. MOSCRIP, BOTH OF ADENA, OHIO.

ELECTRIC MOTOR.

Original application filed October 25, 1921, Serial No. 510,322. Dividedand this application filed April This invention relates to animprovement in electric motors, the general object being to provide asafety device to cut oii" the electric current for the motor and therebystop the motor when the supply of oil in the motor journals, hearings oroil cups 1S 1nadequate or becomes exhausted.

In the accompanying drawing, Fig. 1 1s a diagrammatic view of a serieswound motor and my improved safety oiling device electrically connectedtherewith. Fig. 2 is a diagrammatic view of a motor equipped with a pairof float-controlled switches electrically connected in parallel in anelectric circuit having a magnetic switch adapted to control theelectric current for the motor.

In Fig. 1 I show a series wound motor A having a main supply circuit 2in which a double pole switch 3 is adapted to control the electriccurrent supply. Switch 3 is a m-agnetically-operated switch comprising acoil 4; which is connected with the negative wire of circuit 2 and withthe metal frame of motor A. Whenever coil 4 is energized switch 3 isopened instantly and the electric current is cut off from motor A. Oneway to energize coil 3 is to establish a shunt circuit through the frameof the motor, but only temporarily until magnetic switch 3 is closed.Thus, at the left of Fig. 1 I show a shunt circuit 5 controlled byafloat operated gravity switch 6, which switch is held open as long as apredetermined amount of oil re mains in the column or cup 7 attached bypipe 7 to the journal or bearing 8 of the motor. When the oil fallsbelow a predetermined level the switch 6 drops and closes circuit 5 anda part of the current from the main circuit 2 is shunted through circuit5 to the frame of the motor and thence through coil 4, in this wayopening switch 3 to stop the motor and prevent injury to the bearingsthrough lack of oil. Such a safety circuit and device is of value andutility where a motor is infrequently attended or used in remote orinaccessible places as in operating pumps in mines, etc.

In Fig. 2, I show a motor 25 having a pair of oil cups or oil supplycolumns 2626 for the shaft bearings at opposite ends of the motor frame.These cups have floats 27 therein provided with insulated stems 28Serial No. 682,284.

surmounted by carboncontact blocks 29, and each block is adapted to dropupon a pair of contact members 30 connected in multiple with a battery31 and the coil 32 of a magnetic switch 33 which is adapted to controlmain circuit 2 for motor 25. De-

-pletion of the oil in either cup or column 26 will close the batterycircuit and energize the coil 82 of magnetic switch 33 and open saidswitch, thereby stopping the motherein a magnetically operated switch, a

normally de-energized shunt circuit adapted to operate said magneticswitch, a second switch positioned within said shunt circuit andoperated by the amount of oil within said device, said shunt circuitbeing adapted to momentarily energize said magnetic switch to cause itsoperation and the breaking of said main circuit.

2. An electric motor having a bearing oiling device, a main supplycircuit having therein a magnetically operated switch, and a shuntcircuit to said main circuit between the motor and switch, adapted tooperate said magnetic switch and including a closing device governed bythe amount of oil in the bearing, said shunt being adapted to be closedupon the operation of the closing device and broken upon the operationof said magnetic switch. I

3. An electric motor having a bearing oiling device, a main supplycircuit for said motor having therein a magnetically operated switch, ashunt circuit between the switch and motor, including a closing deviceoperable upon the fall of oil within said device and -adapted to operatesaid magnetic switch, said shunt circuit adapted to be momentarilyclosed upon the operation of the closing device and broken upon theoperation of said magnetic switch.

In testimony whereof, I afiix my signature hereto.

SAMUEL 0. reason.

